In the previous tutorials in this series, we have covered how to select, insert, and update records in a database by leveraging ADO in our ASP pages. In this tutorial, we will cover how to delete records in our database. Deleting records
is a common process in the management of organization data. We will use the SQL DELETE statement to delete records from our database.
SQL DELETE Statement
Structured Query Language also known as 'SQL' is the standard language used with most modern database applications. SQL provides us with a mechanism to select, insert,
update and modify records in a database. In this summary, we are going to focus on the SQL DELETE statement. For more in-depth information about SQL, please visit the
SQL section of this site. There are dozens of tutorials to help you better understand the SQL language.
Syntax
DELETE FROM tableName WHERE fieldName='value'
Examples
In this tutorial, we will take a look at two ASP pages. The first example is an ASP page that a user visits to display the records from a database. A user can click on the button for the
employee record that they wish to delete. Here is the HTML code for the first page.
<!DOCTYPE html>
<html>
<head>
<title>Employees</title>
<style type="text/css">
table {border:1px solid #ABABAB;border-collapse:collapse;color:#4F4F4F;}
th {border:1px solid #ABABAB;background-color:#5F5F5F;color:#FFFFFF;padding:5px;}
tr {border:1px solid #ABABAB;}
td {border:1px solid #ABABAB;padding:5px;}
.btn {width:25px;border:1px solid gray;}
</style>
</head>
<body>
<%
Dim oConn, oRs, ds
ds = "Driver={MySQL ODBC 3.51 Driver};SERVER=db-hostname;DATABASE=db-name;UID=userID;PWD=password"
Set oConn=Server.CreateObject("ADODB.Connection")
OConn.Open ds
Set oRs=Server.CreateObject("ADODB.Recordset")
oRs.open "SELECT * FROM employees",oConn
%>
<h1>Employees</h1>
<table>
<tr>
<%
for each x in oRs.Fields
Response.Write("<th>" & UCase(x.name) & "</th>")
next
%>
</tr>
<% do until oRs.EOF %>
<tr>
<form method="post" action="employeeDelete.asp">
<%
for each x in oRs.Fields
if lcase(x.name)="id" then%>
<td>
<input type="submit" name="id" class="btn" value="<%=x.value%>">
</td>
<%else%>
<td><%Response.Write(x.value)%></td>
<%end if
next
%>
</form>
<%oRs.MoveNext%>
</tr>
<%
loop
oConn.close
%>
</table>
</body>
</html>
When the user clicks on the button in the "ID" field, the user will be taken to a page called "employeeDelete.asp". The following example includes the ASP/ADO code that is needed to present the user with the required
input elements so that the information about the specific record can be deleted in the database record.
<!DOCTYPE html>
<html>
<head>
<title>Update</title>
<style type="text/css">
table {border:1px solid #ABABAB;border-collapse:collapse;color:#4F4F4F;}
tr {border:1px solid #ABABAB;}
td {border:1px solid #ABABAB;padding:5px;}
.btn {border:1px solid gray;}
</style>
</head>
<body>
<%
Dim oConn, oRs, empID, sql
ds = "Driver={MySQL ODBC 3.51 Driver};SERVER=db-hostname;DATABASE=db-name;UID=userID;PWD=password"
Set oConn=Server.CreateObject("ADODB.Connection")
OConn.Open ds
empID = Request.Form("id")
If Request.Form("empName")="" then
Set oRs=Server.CreateObject("ADODB.Recordset")
oRs.open "SELECT * FROM employees WHERE id ='" & empID & "'",oConn
%>
<form method="post" action="employeeDelete.asp">
<table>
<%for each x in oRs.Fields%>
<tr>
<td><%=x.name%></td>
<td><input name="<%=x.name%>" value="<%=x.value%>"></td>
<%next%>
</tr>
</table>
<br /><br />
<input type="submit" class="btn" value="Update record">
</form>
<%
Else
sql="DELETE FROM employees WHERE id = '" & empID & "'"
on error resume next
oConn.Execute sql
If err<>0 then
Response.Write("Error updating Record!")
Else
Response.Write("Record " & empID & " was updated!")
End If
End if
oConn.close
%>
</body>
</html>
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